An organic transistor includes: a substrate made of electrically conductive material or semiconductor material; an insulating layer on the substrate; and an organic semiconductor layer and a pair of electrodes on the insulating layer, wherein a configuration is made such that: the organic semiconductor layer is sealed by a translucent member; a voltage is applied between the pair of electrodes in a range such that the organic semiconductor layer emits light; further a voltage is applied to the substrate so as to control the light emission of the organic semiconductor layer; and light emitted by the organic semiconductor layer can be taken out via the translucent member.
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4. A display device comprising:
an organic transistor substrate, in which a plurality of the organic transistors are arranged, wherein
the organic transistors include,
an electrode layer, an insulating layer and an organic semiconductor layer disposed on a substrate in this order,
a pair of electrodes disposed to be electrically conductive to said organic semiconductor layer, wherein a configuration is further made such that said organic semiconductor layer is sealed, a voltage applied between said pair of electrodes causes said organic semiconductor layer to emit light, and a voltage applied to said electrode controls the light emission, and
said substrate, said electrode layer and said insulating layer are made of translucent material, so that light emitted by said semiconductor layer can be taken out from a side of said substrate; and
light emission of the organic transistors of said organic transistor unit is configured to be turned on/off.
7. A display device comprising:
a light emitting substrate in which a plurality of organic transistors are arranged on a substrate, each of said plurality of organic transistors includes,
a pair of electrodes including a first electrode and a second electrode,
an organic semiconductor layer provided between said pair of electrodes, and
a third electrode provided on the organic semiconductor layer via an insulating layer, wherein
a voltage applied between said pair of electrodes causes said organic semiconductor layer to emit light, and
a voltage applied to said third electrode controls the light emission; and
an optical filter at a position such as to face a light emitting surface of said light-emitting substrate, wherein
said pair of electrodes is configured such that an area from which said organic semiconductor layer emits light has an elongated shape,
said optical filter has a corresponding elongated shape, and
said light-emitting substrate and the filter are laminated.
1. A display device comprising:
an organic transistor substrate, in which a plurality of organic transistors are arranged, wherein
the organic transistors include,
a substrate,
a pair of electrodes comprising a first electrode and a second electrode,
an organic semiconductor layer provided between said first and second electrodes, and
a third electrode, through an insulating layer, in an area in which said organic semiconductor layer is provided between said pair of electrodes, wherein
a configuration is made such that a voltage applied between said pair of electrodes causes said organic semiconductor layer to emit light and a voltage applied to said third electrode controls the light emission of the organic semiconductor layer, and
said substrate is made of translucent material so that light emitted by the organic semiconductor layer can be taken out from a side of said substrate; and
light emission of the organic transistors of said organic transistor unit is configured to be turned on/off.
2. The display device of
3. The display device of
5. The display device of
6. The display device of
8. The display device as claimed in
three of the elongated light emitting areas are arranged side by side so that an approximately square light emitting area is obtained,
correspondingly, three of the optical filters are arranged side by side so that an approximately square shape is obtained, and
the optical filters comprise those for three colors, and also, a filter area for the three colors forms an approximately square area.
9. The display device as claimed in
three elongated light emitting areas are arranged side by side so that an approximately square light emitting area is obtained,
correspondingly, three optical filters are arranged side by side so that an approximately square shape is obtained, and
the optical filters include those for three colors, and also, a filter area for the three colors forms an approximately square area.
10. The display device according to
11. The display device according to
12. The display device according to
13. The display device according to
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1. Field of the Invention
The present invention relates to an organic transistor and associates, and, in particular, to an organic thin-film transistor having light emission function, as well as a display device employing it.
2. Description of the Related Art
Along with a spread of each type of information terminal unit, an improvement of performance and a variety of the devices are demanded. Specifically, needs for a flat panel display device as a display device for a computer has been increasing. Further, along with a development of information society, occasions of providing information in an electronic form instead of a form of paper has been increasing. Thereby, needs for an electronic paper or a digital paper as a mobile display medium which is thin and has a light weight, so that it is easier for carrying, are increasing.
Generally speaking, a display medium employing a device of liquid crystal, organic EL, electrophoretic effect or such, is provided in a flat-type display device. In such a display medium, in order to ensure uniformity of screen brightness and/or screen rewriting speed, an art of using an active driving device made of a thin-film transistor (TFT) is mainly employed for the image driving device. The TFT device is produced as a result of, commonly, on a glass substrate, mainly a semiconductor thin-film such as that of a-Si (amorphous silicon), p-Si (polysilicon) or such, a metal thin-film for a source, a drain and a gate electrodes, and so forth, being laminated in sequence. For producing a flat-panel display device employing the TFT device, commonly, in addition to a thin-film producing process employing a vacuum equipment for CVD, spattering or such, a high-temperature processing process and so forth, a photolithographic process requiring a high accuracy, are required. Therefore, equipment costs and running costs may become very high. Further, along with recent needs for an increase in a size of the display screen, a cost increasing rate along with manufacturing it has becomes very high.
Recently, research and development of an organic TFT device employing an organic semiconductor material is proceeded with (see Japanese Laid-open Patent Application No. 10-190001 and the Advanced Materials journal, 2002, No. 2, page 99 (review)). According to SID, '02 Digest, page 57, since the organic TFT device can be produced in a low temperature process, a resin substrate which has a light weight and is hard to be broken, can be employed instead of a glass substrate which has a heavy weight and is easy to be broken. Further, according to the same document, a flexible display device employing a resin film as a supporting body will be realized. Further, as a result of employing an organic semiconductor material which can be produced in a wet process such as printing, coating or such under an atmospheric pressure being employed, a display device of a very reduced cost with a superior productivity can be realized.
On the other hand, as part of research result of such an organic TFT device employing organic semiconductor material, a light emitting type transistor is reported (see Extended Abstracts (The 65th Autumn Meeting, 2004), Japan Society of Applied Physics, page 1163). By using it, a display device having a new configuration in which a display medium and an image driving device can be integrated, may be realized.
However, this research is in an initial stage in which a light emitting phenomenon has been confirmed. Further research is required for a specific scenario as to how to produce a display device applying this art. The present invention has been devised in consideration of such a situation.
A first object of a first aspect of the present invention is to propose an organic light-emitting transistor having new configuration and function.
A second object of the first aspect of the present invention is to propose new configurations by which such a display device can be stably operated.
A third aspect of the first aspect of the present invention is to propose a display device employing the organic light-emitting transistor.
A first organic transistor includes: a substrate made of electrically conductive material or semiconductor material; an insulating layer on the substrate; and an organic semiconductor layer and a pair of electrodes on the insulating layer, wherein a configuration is made such that: the organic semiconductor layer is sealed by a translucent member; a voltage is applied between the pair of electrodes in a range such that the organic semiconductor layer emits light; further a voltage is applied to the substrate so as to control the light emission of the organic semiconductor layer; and light emitted by the organic semiconductor layer can be taken out via the translucent member.
As a result, an organic light-emitting transistor having a new configuration by which transistor operation and light-emitting operation can be carried out in a single device can be proposed.
A second organic transistor includes a substrate; a pair of electrodes including a first electrode and a second electrode; an organic semiconductor layer provided between the first and second electrodes; and a third electrode, through an insulating layer, in an area in which the organic semiconductor layer is provided between the pair of electrodes, wherein: a configuration is made such that: a voltage is applied between the pair of electrodes in a range such that the organic semiconductor layer emits light; further a voltage is applied to the third electrode so as to control the light emission of the organic semiconductor layer; and the substrate is made of translucent material so that light emitted by the organic semiconductor layer can be taken out from a side of the substrate.
As a result, an organic light-emitting transistor having another new configuration by which transistor operation and light-emitting operation can be carried out in a single device can be proposed.
A third organic transistor includes: a substrate; a pair of electrodes including a first electrode and a second electrode; an organic semiconductor layer provided between the first and second electrodes; and a third electrode, through an insulating layer, in an area in which the organic semiconductor layer is provided between the pair of electrodes, wherein: a configuration is made such that: a voltage is applied between the pair of electrodes in a range such that the organic semiconductor layer emits light; further a voltage is applied to the third electrode so as to control the light emission of the organic semiconductor layer; and the insulating layer and the third electrode are made of translucent material so that light emitted by the organic semiconductor layer can be taken out from a side of the third electrode.
As a result, an organic light-emitting transistor having another new configuration by which transistor operation and light-emitting operation can be carried out in a single device can be proposed.
A fourth organic transistor is configured such that: an electrode layer, an insulating layer and an organic semiconductor layer are produced on a substrate in the stated order; and a pair of electrodes are produced to be electrically conductive to the organic semiconductor layer, wherein a configuration is further made such that: the organic semiconductor layer is sealed; a voltage is applied between the pair of electrodes in such a range that the organic semiconductor layer emits light; a voltage is further applied to the electrode layer so as to control the light emission; and the substrate, the electrode layer and the insulating layer are made of translucent material, so that light emitted by the semiconductor layer can be taken out from a side of the substrate.
As a result, an organic light-emitting transistor having another new configuration by which transistor operation and light-emitting operation can be carried out in a single device can be proposed.
A fifth organic transistor is configured such that: an electrode layer, an insulating layer and an organic semiconductor layer are produced on a substrate in the stated order; and a pair of electrodes are produced to be electrically conductive to the organic semiconductor layer, wherein a configuration is further made such that: the organic semiconductor layer is sealed by a translucent member; a voltage is applied between the pair of electrodes in such a range that the organic semiconductor layer emits light; a voltage is further applied to the electrode layer so as to control the light emission; and light emitted by the semiconductor layer can be taken out through the translucent member.
As a result, an organic light-emitting transistor having another new configuration by which transistor operation and light-emitting operation can be carried out in a single device can be proposed.
A first organic transistor unit includes an organic transistor substrate, in which a plurality of organic transistors each of which is the same as any one of the above-mentioned first through fifth organic transistors, are arranged, disposed in a vacuum airtight state.
As a result, in addition to the above-mentioned advantage, a device function can be stably provided.
A second organic transistor unit includes an organic transistor substrate, in which a plurality of the organic transistors each of which is the same as any one of the above-mentioned first through fifth organic transistors, are arranged, disposed in an inert-gas atmosphere.
As a result, in addition to the above-mentioned advantage, a device function can be stably provided.
A display device includes the above-mentioned first or second organic transistor unit, wherein: light emission of the organic transistors of the organic transistor unit is turned on/off.
As a result, a self light emitting type display device having a new configuration by which transistor operation and light-emitting operation can be carried out in a single device can be proposed.
A first object of a second aspect of the present invention is to propose an organic transistor having new configuration and function.
A second object of the second aspect of the present invention is to propose a configuration by which the organic transistor can be operated more effectively.
A third object of the second aspect of the present invention is to provide a new configuration when a plurality of the organic transistors are arranged.
A fourth object of the second aspect of the present invention is to provide a new configuration by which the organic transistor can be stably operated.
A fifth object of the second aspect of the present invention is to provide a display device employing the organic light-emitting transistors.
In order to achieve these objects of the second aspect of the present invention, a first organic transistor includes a substrate; a pair of electrodes; and an organic semiconductor layer on the substrate between the pair of electrodes, wherein: the substrate is made of an electrically conductive material or a semiconductor material, and has an insulating layer thereon; the organic semiconductor layer and the pair of electrodes are produced on the insulating layer; a part of (a top surface of) the organic semiconductor layer is sealed by a translucent member (sealing structure); a voltage is applied between the pair of electrodes in such a range that the organic semiconductor layer emits light; and further a voltage is applied to the substrate so as to control the light emission of the organic semiconductor layer.
As a result, transistor operation and light-emitting operation can be carried out in a single device.
A first organic transistor unit includes a plurality of organic transistors each of which is the same as the above-mentioned first organic transistor disposed on the substrate.
As a result, in addition to the above-mentioned advantage, application in a self light emitting type display device can be made possible.
In a second organic transistor unit, in the sealing structure, the translucent member is provided separately for each organic transistor in the first organic transistor unit.
As a result, in addition to the above-mentioned advantage, each device can be positively sealed, and thus, performance of each particular device can be stabilized.
In a third organic transistor unit, in the sealing structure, the plurality of organic transistors are sealed by the translucent member in such a manner as to seal the plurality of organic transistors by the single translucent member in the first organic transistor unit.
As a result, in addition to the above-mentioned advantage, manufacturing costs can be reduced.
In the first organic transistor or in any one of the first through third organic transistor units, a vacuum layer may be inserted between the organic semiconductor layer and the translucent member.
As a result, in addition to the above-mentioned advantage, the device performance can be stably provided.
In the first organic transistor or in any one of the first through third organic transistor units, the organic semiconductor layer may be disposed in an inert-gas atmosphere.
As a result, in addition to the above-mentioned advantage, the device performance can be stably provided with age.
In the first organic transistor or in any one of the first through third organic transistor units, the organic semiconductor layer and the translucent member may be made in contact with one another.
As a result, in addition to the above-mentioned advantage, the device performance can be stably provided.
A display device includes organic transistors each of which is the same as the first organic transistor or includes an organic transistor unit the same as any one of the first through third organic transistor units, wherein: light emission amounts of the organic transistors are changed gradually/stepwise.
As a result, a self light emitting type display device having a new configuration such that transistor operation and light-emitting operation can be carried out in a single device, and also, tone expression can be carried out can be proposed.
A first object of a third aspect of the present invention is to propose an organic light-emitting transistor having new configuration and function.
A second object of the third aspect of the present invention is to propose a specific configuration of the organic light-emitting transistor.
A third object of the third aspect of the present invention is to propose a new configuration by which the organic light-emitting transistor can be made to stably function.
A fourth object of the third aspect of the present invention is to provide a display device employing the organic light-emitting transistors.
A fifth object of the third aspect of the present invention is to provide a color display device employing the organic light-emitting transistors.
In order to achieve these objects of the third aspect of the present invention, a first organic transistor includes: a pair of electrodes comprising a first electrode and a second electrode; an organic semiconductor material provided between the pair of electrodes; and a third electrode through an insulating layer in an area in which the organic semiconductor material is provided, wherein: a voltage is applied between the pair of electrodes in such a range that the organic semiconductor material emits light; and a voltage is further applied to the third electrode so as to control the light emission, wherein: a length of the pair of electrodes in an area in which the pair of electrodes face one another is longer than a distance between the pair of electrodes.
As a result, an organic light-emitting transistor having a new configuration by which transistor operation and light-emitting operation can be carried out in a single device can be proposed. Further, in this organic light-emitting transistor, the electrode length in the area in which the pair of electrodes face one another is made longer than the inter-electrode distance between the pair of electrodes. As a result, very high light-emitting efficiency can be achieved.
A second organic transistor is configured such that, in the first organic transistor, the pair of electrodes have comb tooth like shapes on sides facing one another; and the comb tooth shapes are such that they pass each other.
As a result, the electrode length in the area in which the pair of electrodes face one another can be made efficiently longer. As a result, the organic light-emitting transistor having a very high light-emitting efficiency can be achieved.
A third organic transistor is configured such that, in any of the first and second organic transistors, the pair of electrodes are configured so that: the organic semiconductor material is made to emit light in an area in which the pair of electrodes face one another; and an area of the light emission has an elongate shape.
As a result, an organic light-emitting transistor having another new configuration by which transistor operation and light-emitting operation can be carried out in a single device can be proposed.
A fourth organic transistor is configured such that, in any of the first through third organic transistors, a plurality of light emission areas in which the pair of electrodes face one another are produced in a matrix-like arrangement; and each light emission area has an elongate shape such that adjacent three light emission areas produce an approximately square shape.
As a result, an organic light-emitting transistor having another new configuration by which transistor operation and light-emitting operation can be carried out in a single device can be proposed.
A first organic transistor unit includes an organic transistor substrate in which a plurality of the organic transistors, each of which is the same as any of the first through fourth organic transistors, are arranged is disposed in a vacuum airtight state.
As a result, in addition to the above-mentioned advantage, the device performance can be stably provided.
A second organic transistor unit includes an organic transistor substrate in which a plurality of the organic transistors, each of which is the same as any of the first through fourth organic transistors, are arranged is disposed in an inert-gas atmosphere.
As a result, in addition to the above-mentioned advantage, the device performance can be stably provided.
A display device includes the first or second organic transistor unit, wherein: light emission of the organic transistors of the organic transistor unit is turned on/off.
As a result, a self light-emitting display device having a new configuration by which transistor operation and light-emitting operation can be carried out in a single device can be proposed.
A color display device is configured such that in the first display device, a filter is disposed at a position to face a light emission surface of the organic transistors.
As a result, a self light-emitting color display device having a new configuration by which transistor operation and light-emitting operation can be carried out in a single device can be proposed.
A first object of a fourth aspect of the present invention is to propose an organic light-emitting transistor having new configuration and function.
A second object of the fourth aspect of the present invention is to propose a specific configuration of the organic light-emitting transistor.
A third object of the fourth aspect of the present invention is to propose a new configuration by which the organic light-emitting transistor can be made to stably function.
A fourth object of the fourth aspect of the present invention is to provide a display device employing the organic light-emitting transistors.
In order to achieve these objects of the fourth aspect of the present invention, a first organic transistor includes: a pair of electrodes including a first electrode and a second electrode; an organic semiconductor layer provided between the pair of electrodes; and a third electrode provided on the organic semiconductor layer via an insulating layer, wherein: a voltage is applied between the pair of electrodes in such a range that the organic semiconductor layer emits light; and a voltage is further applied to the third electrode so as to control the light emission, wherein: the third electrode includes a patterned electrode made of a translucent member; and the patterned electrode covers an area wider than an area in which the organic semiconductor layer emits light.
As a result, an organic light-emitting transistor having a new configuration by which transistor operation and light-emitting operation can be carried out in a single device can be proposed. Further, since no edge of the electrode pattern is provided in the light-emitting area, a better light emitting part, without being obstructed by the electrode pattern edge, can be achieved.
A second organic transistor is configured such that, in the first organic transistor, the organic semiconductor layer and the pair of electrodes are produced on a substrate; and the third electrode is produced on the organic semiconductor layer via the insulating layer made of a translucent member.
As a result, an organic light-emitting transistor having a more specific new configuration by which transistor operation and light-emitting operation can be carried out in a single device can be proposed.
A third organic transistor is configured such that, in the first organic transistor, on a substrate made of a translucent member, the third electrode, the insulating layer made of a translucent member and the organic semiconductor layer are produced in the stated order; and the pair of electrodes made electrically conductive to the organic semiconductor layer are produced.
As a result, an organic light-emitting transistor having another specific new configuration by which transistor operation and light-emitting operation can be carried out in a single device can be proposed.
A first organic transistor unit includes an organic transistor substrate in which a plurality of the organic transistors, each of which is the same as any of the first through third organic transistors, are arranged is disposed in a vacuum airtight state.
As a result, in addition to the above-mentioned advantage, the device performance can be stably provided.
A second organic transistor unit includes an organic transistor substrate in which a plurality of the organic transistors, each of which is the same as any of the first through third organic transistors, are arranged is disposed in an inert-gas atmosphere.
As a result, in addition to the above-mentioned advantage, the device performance can be stably provided.
A display device includes the first or second organic transistor unit, wherein: light emission of the organic transistors of the organic transistor unit is turned on/off.
As a result, a self light-emitting display device having a new configuration by which transistor operation and light-emitting operation can be carried out in a single device can be proposed.
A first object of a fifth aspect of the present invention is to propose a specific configuration of a display device employing an organic light-emitting transistor having new configuration and function.
A second object of the fifth aspect of the present invention is to propose a new configuration by which the display device can be stably operated.
In order to achieve the objects of the fifth aspect of the present invention, a first display device includes a light emitting substrate in which a plurality of organic transistors are arranged, each of the plurality of organic transistors includes: a pair of electrodes, i.e., a first electrode and a second electrode; an organic semiconductor material provided between the pair of electrodes; and a third electrode provided on the organic semiconductor layer via an insulating layer, wherein: a voltage is applied between the pair of electrodes in such a range that the organic semiconductor layer emits light; and a voltage is further applied to the third electrode so as to control the light emission; and an optical filter at a position such as to face a light emitting surface of the light-emitting substrate, wherein: the pair of electrodes is configured such that an area from which the organic semiconductor layer emits light has an elongate shape; and the optical filter is produced to have a corresponding elongate shape.
As a result, a display device having a new configuration by which transistor operation and light-emitting operation can be carried out in a single device, and also, having a high light-emitting efficiency, can be proposed.
A second display device is configured such that, in the first display device, three of the elongate light emitting areas are arranged side by side so that an approximately squire light emitting area is obtained; correspondingly, three of the optical filters are arranged side by side so that an approximately squire shape is obtained; the optical filters include those for three colors, and also, a filter area for the three colors forms an approximately square area.
As a result, in addition to the above-mentioned advantage, a color display device providing a high grade display function can be achieved.
A third display device is configured such that, in the first or second display device, the light-emitting substrate and the filter are laminated; and the laminated device thus obtained is disposed in a vacuum airtight state.
As a result, in addition to the above-mentioned advantage, the device performance can be stably provided.
A fourth display device is configured such that, in the first or second display device, the light-emitting substrate and the filter are laminated; and the laminated device thus obtained is disposed in an inert-gas atmosphere.
As a result, in addition to the above-mentioned advantage, the device performance can be stably provided.
A fifth display device is configured such that, in the first or second display device, the light-emitting substrate and the filter are laminated; and an area from which the organic semiconductor layer emits light is made in a vacuum airtight state.
As a result, in addition to the above-mentioned advantage, the device performance can be stably provided, and also, the configuration can be simplified.
A sixth display device is configured such that, in the first or second display device, the light-emitting substrate and the filter are laminated; and an area from which the organic semiconductor layer emits light is disposed in an inert-gas atmosphere.
As a result, in addition to the above-mentioned advantage, the device performance can be stably provided, and also, the configuration can be simplified.
Other objects and further features of the present invention will become more apparent from the following detailed description when read in conjunction with the accompanying drawings:
Embodiments of the present invention will now be described with reference to figures.
The light emitting type organic thin-film transistor device according to the present invention is generally classified into a top gate type and a bottom gate type. A light emitting type organic thin-film transistor device according to the present invention in the top gate type has a source electrode and a drain electrode, in contact with an organic semiconductor layer, on a supporting body, and further thereon, has a gate electrode through a gate insulating layer. In the bottom gate type, a gate electrode is provided on a supporting body first, and a source electrode and a drain electrode are provided which are joined by means an organic semiconductor layer, through a gate insulating layer. Specific layer structure examples of the devices (sectional views of single devices) are shown in
As will be described later, as a material of the substrate of the supporting body 1, a translucent material may be used, so that light can be taken out from the side of the supporting body 1 (in a direction of an arrow A of
Alternatively, also description will be made later for a material and so forth, and the gate insulating layer 5 and the gate electrode 6 may be made of translucent material, so that light can be taken out from the side of the gate electrode 6 (in a direction of an arrow B of
As the substrate material of the supporting body 1, as will be described later, translucent material may be used. Further, also the gate electrode 6 and the gate insulating layer 5 may be made of translucent material as will be described later. Thereby, light can be taken out from the side of the supporting body 1 (in a direction of an arrow A of
Attentively, the device protection layer 7 may be made of translucent material such as silicon oxide, and a sealing structure may be provided. As a result, light can be taken out in a direction of an arrow B of
Then, a voltage is applied between the source and drain electrodes 3 and 4 in such a range that the organic semiconductor layer 2 emits light. Further, a voltage is applied to the gate electrode 6 to control the light emission.
By configuring the device protection layer 7 of translucent material such as silicon oxide, light can be taken out in a direction of an arrow A of
As will be described later, when sealing is carried out in such a form that the entirety of the organic transistor is made in a vacuum airtight condition or disposed in an inert-gas atmosphere, the device protection layer 7 is not required.
As material of the organic semiconductor layer employed in the light emitting type organic thin-film transistor device, pi-conjugated material is used. For example, polypyrrole, a polypyrrole family such as poly(N-substituted pyrrole), poly(3-substituted pyrrole), poly(3,4-disubstituted pyrrole), a polythiophene family such as poly(3-substituted thiophene), poly(3,4-disubstituted thiophene), polybenzothiophene, a polyisobenzothiofuran family such as polyisobenzothiofuran, polythienylenevinylene family such as polythienylenevinylene, a poly(p-phenylenevinylene) family such as poly(p-phenylenevinylene), a polyaniline family such as polyaniline, poly(N-substituted aniline), poly(3-substituted aniline), poly(2,3-substituted aniline), a polyacetylene family such as polyacetylene, a polydiacetylene family such as polydiacetylene, a polyazulene family such as polyazulene, a polypyrene family such as polypyrene, a polycarbazole family such as polycarbazole, poly(N-substituted carbazole), a polyselenophene family such as polyselenophene, a polyfuran family such as polyfuran, polybenzofuran, a poly(p-phenylene) family such as poly(p-phenylene), a polyindole family such as polyindole, pyridazine family such as pyridazine, a polyacene family such as naphthacene, pantacene, hexacene, heptacene, dibenzopentacene, tetrabenzopantacene, pyrene, dibenzopyrene, chrysene, perylene, coronene, terylene, ovalene, quoterylene, circumanthracene, derivative obtained from substitution of part of carbon of the polyacene family (triphenodioxazine, triphenodithiazine, hexacene-6,15-quinone or such), polymer such as polyvinylcarbazole, polyphenylenesulfide, polyvinylenesulfide, may be used.
Further, thiophene hexamer, for example, having same repeating units as those of these polymers, i.e., α-sexithiophene, α,ω-dihexyl-α-sexiothiophene, α,ω-dihexyl-α-quinquethiophene, α,ω-bis(3-butoxypropyl)-α-sexithiophene, or oligomer such as styrylbenzene derivative may be preferably used.
Further, metal phtharosyanene family such as copper phthalocyanine, fluorine-substituted copper phtharosyanene, condensed ring tetracarboxilic acid diimide family such as naphthalene 1,4,5,8-tetracarboxilic acid diimide, N,N′-bis(4-trifluoromethylbenzil)naphthalene 1,4,5,8-tetracarboxilic acid diimide, also, N,N′-bis(1H, 1H-perfluorobutyl), and a naphthalene tetracarboxilic acid diimide family such as N,N′-dioctylnaphthalene 1,4,5,8-tetracarboxilic acid diimide derivative, naphthalene 2,3,6,7 tetracarboxilic acid diimide, and an anthracenetetracarboxilic acid diimide family such as anthracene 2,3,6,7 tetracarboxilic acid diimide, a fullerene family such as C60, C70, C76, C78, C84, carbon nanotube such as SWNT, a dye family such as a merocyanine dye family, hemicyanine dye family, may be used.
Among these pi-conjugate materials, one of a group of oligomer having the number of repeating units n in a range between 4 and 10, or polymer having the number of repeating units n more than 20, in which thiophene, vinylene, thienyrelenvinylene, phenylenevinylene, p-phenylene, substation thereof, or a plurality thereof is used as a repeating unit, polycyclic aromatic compound such as pentacene, a fullerene family, a condensed ring tetracarboxilic acid diimide family and metal phthalocyanine, may be preferable.
As another organic semiconductor material, organic molecular complex such as tetrathiafulvalene (TTF)-tetracyanoquinodimetane (TCNQ) complex, bisethylenetetrathiafulvalene (BEDTTTF)-perchloric acid complex, BEDTTTF-iodine complex or TCNQ-iodine complex may be used. Further, σ conjugate polymer such as polysilane or polygermane may be used.
The light emitting type organic semiconductor material according to the present invention has, for example, as a main ingredient, copolymer having a repeating unit expressed by the following general formula. The material will be described in detail including a method of producing the same.
##STR00001##
For example, in a carboxyl group expressed by the flowing general formula (I), and a phosphate compound expressed by the following general formula (II) are reacted, and a copolymer having a repeating unit of the following general formula (III) is produced.
##STR00002##
In the general formula (I), A1, A2 denote substituted or non-substituted monocyclic or polycyclic arylene group or heteroarylene group. R1 denotes hydrogen, substituted or non-substituted alkyl group, or substituted or non-substituted aryl group. V denotes O—, —S— or —NR2-. R2 denotes substituted or non-substituted monocyclic or polycyclic arylene group, or, substituted or non-substituted monocyclic or polycyclic heteroarylene group. Further, n≧0.
In the general formula (II), A3, A4 denote substituted or non-substituted monocyclic or polycyclic arylene group or heteroarylene group. R3 denotes hydrogen, substituted or non-substituted alkyl group, aryl group or heteroaryl group. W denotes —O—, —S— or —NR4-. R4 denotes substituted or non-substituted monocyclic or polycyclic arylene group, or, substituted or non-substituted monocyclic or polycyclic heteroarylene group. Further, m≧0. X denotes PO(OR5) or P(R6)3+Y—. R5 denotes lower alkyl group. R6 denotes substituted or non-substituted aryl group, or, substituted or non-substituted alkyl group. Y denotes halogen atom.
Below further details are described.
Preferably usable base compound preferably used includes all of generally known base compounds as long as they are dissolved uniformly in nonaqueous solvent. However, in consideration of organization potency of phosphonate carbanion, in a basicity viewpoint, metal alcoxide, metal hydride, organic lithium compound or such is preferable. For example, potassium t-butoxide, sodium t-butoxide, lithium t-butoxide, potassium 2-methyl-2-butoxide, sodium 2-methyl-2-butoxide, sodium-methoxide, sodium-ethoxide, potassium-ethoxide, potassium-methoxide, sodium hydride, potassium hydride, methyl lithium, ethyl lithium, propyl lithium, n-butyl lithium, s-butyl lithium, t-butyl lithium, phenyl lithium, lithium naphtylide, lithium amide, lithium diisopropyl amide, or such may be used.
As the solvent dissolving base, solvent which can provide stable solution with base should be selected. Another factor is that one having high solubility of base is preferable. Further, one which does not degrade solubility with respect to high molecular weight reaction solvent which is produced in a reaction system is preferable. Depending on base to use and property of high molecular weight substance to produce, any one may be selected from generally known alcoholic solvent, ether solvent, amin solvent, hydrocarbon solvent and so forth.
As a combination of base and solvent to which the base is uniformly dissolved, solutions of various combinations may be used, such as methanol solution of sodium methoxide, ethanol solution of sodium ethoxide, 2-propanole solution of potassium t-butoxide, 2-methyl-2-propanonle solution of potassium t-butoxide, tetrahydrofuran solution of potassium t-butoxide, dioxane solution of potassium t-butoxide, hexane solution of n-butyl lithium, ether soliution of methyl lithium, tetrahydrofuran solution of lithium t-butoxide, cyclohexane solution of lithium diisopropyl amide, toluene solution of potassium bistrimethyl silyl amide or such. Some of them may be easily obtained as commercial items. In viewpoints of mild reaction condition, easiness in handling, solution of metal alcoxide may be preferably used. In viewpoints of solubility of polymer to produce, easiness in handling of the same, efficiency of reaction, ether solution of metal t-butoxide may be used more preferably. Further preferably, tetrahydrofuran solution of potassium t-butoxide may be used.
Solution stoichimetrically equally including phosphorous compound and aldehyde compound, and the above-described base solution including base in the double molar amount may be mixed, and thus, polymerization reaction will easily progress. Thus, polymer of a high molecular weight, preferably controlled in a narrow molecular weight distribution can be easily obtained. Ordinarily, an amount of base which should be used is an equal amount with respect to a polymerization active spot of phosphorus compound. However, no problem occurs when an excessive amount is used.
The above-mentioned polymerization reaction may also be made as a result of base solution being added to solution of phosphorus compound and aldehyde compound, as a result of solution of phosphorous compound and aldehyde compound being added to base solution, or, as a result of they being added at the same time to a reaction system. No limitation exists for an order of the addition.
Polymerization time required for the above-mentioned polymerization should be set appropriately depending on reactivity of monomer to use, a molecular weight of polymer to obtain, or such. 0.2 through 30 hours is preferable. Further, sealant for sealing an end of polymer may be added during the reaction or after the reaction. The same may be added at the time of beginning of the reaction.
Control of reaction temperature in the above-mentioned polymerization is not required. The reaction sufficiently will progress even at a room temperature. Heating may be made for the purpose of increasing reaction efficiency, or, cooling may be made for the purpose of obtaining mild condition.
Embodiments will now be described for further specific examples. However, embodiments of light emitting type organic semiconductor material are not limited thereto as long as its basic concept is not deviated from.
Various sorts of measurements were carried out as follows: Measurements of polymer's number average molecular weight (Mn), weight average molecular weight (Mw) and molecular weigh distribution (Mw/Mn) were carried out with the use of a gel permeation chromatography (GPC). By using UV absorption and differential refractive index, the measurements were carried out on a polystyrene equivalent basis with monodisperse polystyrene as a standard.
<Material Producing Embodiment>
In a 100 ml four-neck flask, 0.852 g (2.70 mmol) of dialdehyde expressed by the following formula:
##STR00003##
and 1.525 g (2.70 mmol) of diphosphonate expressed by the following formula:
##STR00004##
were put. Nitride substitution was carried out, and then, 75 ml of tetrahydrofuran was added. In this solution, 6.75 ml (6.75 mmol) of potassium-butoxide's 1.0 mol dm-3 tetrahydrofuran solution was dropped. Then, stirring was carried out for 20 hours at a room temperature. After that, benzylphosphonate and benzaldehyde were added in sequence. Then, stirring was carried out for 2 hours 30 minutes. Finally, approximately 1 ml of acetic acid was added. Thus, reaction was finished. Then the solution was washed. Therefrom, solvent was extracted under reduced pressure. Purification was carried out from the residual with the use of 15 ml of tetrahydrofuran and 80 ml of methanol. Thus, 1.07 g of polymer expressed by the following chemical formula was obtained:
##STR00005##
A molecular weight and molecular weight distribution of the thus-obtained were measured. As a result, data of the polymer was as follows: yield: 73%, weight average molecular weight (Mw): 104000; numeral average macular weight (Mn): 36000; molecular weight distribution (Mw/Mn): 2.89; and polymer: 63.
The above-mentioned embodiment is one example, and, other material may be used. For example, from substance, such as pantacene, having precursor soluble in solvent, a film of the precursor, produced by means of a liquid spraying principle or such described later, may be processed thermally, and may be used for producing a thin film of organic material as the object material.
From the light emitting type organic semiconductor material according to the present invention thus obtained, which is high-molecular weight polymer, a satisfactory thin film having superior strength, ductility and durability and so forth, without cracks, can be produced by means of a well-known film forming method such as a spin coat method, a cast method, a dip method, a liquid spray method, a doctor blade method, a screen printing method, or such.
Especially, a method of liquid spraying principle (which may be called ‘ink jet method’) is an art having high general purpose properties and thus may be applied for an electrode pattern production described later. Thus, this method may be effectively used for producing a light emitting type organic thin-film transistor device according to the present invention. A result of study for a manufacturing apparatus for carrying out this method will now be described.
As liquid drop providing devices (jetting head 33) of the jetting head 11, any mechanism may be used as long as it can jet a predetermined amount of liquid drop. Especially, a mechanism according to an ink jet principle which can produce a liquid drop on the order of 0.05 pl through several hundreds of pl is preferable.
As the ink jet method, one which is generally called a drop on demand method may be used in which, as disclosed by U.S. Pat. No. 3,683,212 (Zoltan method), U.S. Pat. No. 3,747,120 (Stemme method) or U.S. Pat. No. 3,946,398 (Kyser method), an electrical signal is applied to a piezo vibration device, the electrical signal is transformed into a mechanical vibration, and liquid drops are jetted so as to fly from fine nozzles according to the mechanical vibration.
Alternatively, a method (Sweet method) disclosed by U.S. Pat. No. 3,596,275 or U.S. Pat. No. 3,298,030 may be used. In this method, according to a continuous vibration generating method, small drops of recording liquid having electrically charge amounts controlled are generated, the generated small drops having the electrically charge amounts controlled are made to fly between deflection electrodes to which a uniform electric field is applied, and thus, recording is made on a recording member. Normally, this method is called a continuous flow method, or an electrical charge control method.
Further alternatively, a method disclosed by Japanese Patent Publication No. 56-9429 may be used. In this method, air bubbles are generated in liquid, and liquid drops are jetted from fine nozzles thanks to functional force of the air bubbles. This method is called a thermal ink jet method or bubble jet method (registered trademark).
Any liquid jetting method may be selected from the drop on demand method, the continuous flow method, the thermal ink jet method and so forth appropriately according to particular requirements.
According to the present invention, in the light emitting type organic thin-film transistor device manufacturing apparatus (
Further, the manufacturing apparatus usable for manufacturing a light emitting type organic thin-film transistor device according to the present invention has a rotational position adjustment mechanism (not shown since it is located under the substrate 14) in addition to the X-Y direction positional adjustment mechanism.
In this relation, a shape of the light emitting type organic thin-film transistor device substrate according to the present invention, an arrangement of a device group to be produced, and so forth, will now be described first.
As the light emitting type organic thin-film transistor device substrate (organic transistor unit) according to the present invention, as will be described later, depending on a purpose or a use thereof, various sorts of plastic substrate such as a glass substrate, a ceramic substrate, PET, a semiconductor substrate such as Si, a glass epoxy substrate, a flexible substrate made of high molecular weight film such as a polyimide film, a polyamideimide film, a polyamide film, a polyester film and so forth may be preferably used. For example, the various sorts of plastic substrates or high molecular weight films may be advantageously used for a pattern writing substrate for which weight reduction is required, or for manufacturing various sorts of functional devices such as light emitting type organic thin-film transistor devices according to the present invention.
Further, during manufacturing such devices, heat may be applied in a mid process. Upon manufacturing a high-accuracy device, degradation in device accuracy due to thermal expansion should be taken into account. For example, according to the present invention, in order to manufacture a high-accuracy light emitting type organic thin-film transistor device, polymer material may be preferably used, which has such a low linear expansion coefficient α (=1/l0·dl/dt, where l0 denotes a length at a temperature of 0° C.; l denotes a length at a temperature of t° C.) that α/K−1=20 through 50×10−6 at 295 K (20° C.) or less, which is near linear expansion coefficient of metal.
As a transparent substrate having such low linear expansion coefficient, for example, composite material in which transparent polymer material is reinforced by transparent nanofiber reinforced fiber in biosystem having a diameter on the order of 50 through 100 nm may be used. Therewith, transmittance of 90 through 95% may be obtained for parallel light.
A shape of various sorts of plastic substrate or a high molecular weight film used as a light emitting type organic thin-film transistor device according to the present invention is a rectangle, for the purpose of economically manufacture, a supply of such a substrate, or for a use of the thus-finally-produced light emitting type organic thin-film transistor device substrate. That is, the substrate to use has vertical two sides, parallel to each other, and horizontal two sides, parallel to each other, and vertical and horizontal sides form a right angle.
According to the present invention, on the substrate, a group of light emitting type organic thin-film transistor devices are arranged in a matrix manner, such that two direction perpendicular to one another of sides of the matrix are parallel to a vertical direction side and a horizontal direction side of the substrate, respectively. A reason why the light emitting type organic thin-film transistor device group is arranged in the matrix manner and a reason why the vertical and horizontal sides of the substrate are made parallel to the perpendicular two directions of the matrix, respectively, will now be described.
In the light emitting type organic thin-film transistor device manufacturing apparatus shown in
Returning to the rotational positional adjustment mechanism, description will now be made. As described above, according to the present invention, the high accuracy light emitting type organic thin-film transistor device matrix arrangement is achieved as a result of accurately positioning the substrate being carried out before light emitting type organic thin-film transistor device producing liquid drop jetting operation, and then, merely mutual movement in X/Y directions is carried out without requiring any other control. A matter to take into account is a possible shift occurring in a rotational direction (a rotational direction about an axis perpendicular to the plane defined by the X/Y directions) which may occur when the substrate is first positioned.
In order to correct the shift in rotation direction, according to the present invention, as mentioned above, the rotational position adjustment mechanism is provided. Thereby, the rotational axis shift is corrected. As a result, in the apparatus according to the present invention, only with mutual movement in the X/Y directions, a high accuracy light emitting type organic thin-film transistor device matrix arrangement can be obtained.
In the above, description has been made assuming that the rotational positional adjustment mechanism is separate from the substrate positioning/holding device 22 (22X1, 22Y1, 22X2, 22Y2) shown in
The above description assumes that the substrate or sheet preferably used in the present invention has basically a rectangular shape. However, as an exception, a semiconductor substrate such as Si is provided in a form of a round wafer, and, in this case, one linear side, called orientation flat, indicating a crystal orientation axis direction, should be made to contact the above-mentioned substrate positioning/holding device 22.
Another configuration for positioning will now be described. In the above description, the substrate positioning/holding device 22 is made to contact the sides of the substrate 14, and the entirety of the substrate positioning/holding device 22 carries out positioning in the X/Y directions. However, in the other configuration described now, different therefrom, other than the sides of the substrate 14, for example, mutually perpendicular belt-like patterns are provided on the substrate. As described above, according to the present invention, on the substrate, a light emitting type organic thin-film transistor device group is arranged in a manner of a matrix. In this example, the above-mentioned mutually perpendicular two-direction band-like patterns are produced in such a manner that the band-like patterns are parallel to the mutually perpendicular two directions of the matrix. These patterns can be easily produced by means of a photo-fabrication technology on the substrate.
Next, with reference to
In this liquid jetting head, a piezo device 46 is provided in a flow path 45 through which solution 56 is introduced, as an energy function part. A pulse-like signal voltage is applied to the piezo device 46, thus the piezo device 46 is deformed as shown in
The solution 56 introduced into the flow path 45 immediately before the nozzle 65 is one already having passed through a filter 57. According to the present invention, the filter 57 is provided in the jetting head, and thus, filtering function is provided nearest to the nozzle 65. Thereby, foreign particles are trapped from the solution according to the present invention, and thus, degradation in performance of the electrode patterns or organic light emitting material patterns produced on the substrate can be avoided. Such a filter 57 may be one which is small-sized simple filter. Thereby, it can be assembled in the jetting head 11 shown in
As such a filter 57, a stainless mesh filter may be preferably used for example. A hole diameter (i.e., filtering mesh size: a lower limit of a size of foreign particle which can be removed therewith) thereof is 0.2 μm through 2 μm.
With reference to
The liquid jetting head shown there is called an edge shooter type one in which a liquid drop is jetted from an end of the flow path in which solution flows.
In the figure, an example where four nozzles are provided is shown. This liquid jetting head is produced as a result of a heating body substrate 66 and a lid substrate 67 being joined. The heating body substrate 66 is produced as a result of, through a wafer process, on a silicon substrate 68, particular electrodes 69, a common electrode 70 and a heating body 71 which is an energy function part, being produced.
On the other hand, in the lid substrate 67, grooves 74 for producing the flow paths and a recess area 75 for producing a common liquid chamber containing the above-mentioned solution to be introduced to the flow paths are produced. These heating body substrate 66 and the lid substrata 67 are joined as shown in
In producing a light emitting type organic thin-film transistor device according to the present invention, light emitting type organic thin-film transistors or electrode patterns are produced by means of a plurality of liquid drops. These are patterns produced as a result of dots being produced in a mutually overlapping manner, or being connected together. Therefore, by using such a multi-nozzle liquid jetting head, a light emitting type organic thin-film transistor device can be very efficiency produced. In this example, the four-nozzle liquid jetting head has been described. However, the number of nozzles is not limited to the four. As the number of nozzles increases, the light emitting type organic thin-film transistor device can be produced more efficiently. However, when the number of nozzles increases, the costs, on the other hand, increases accordingly. Further, a possibility that the nozzles are blocked may increases accordingly. Therefore, the determination should be made in consideration of a balance in the entirety of the apparatus (a balance between the apparatus costs and the light emitting type organic thin-film transistor device producing efficiency).
Symbols A, B, C and D are given to the respective multi-nozzle-type liquid jetting heads. These liquid jetting heads A, B, C and D have nozzle parts configured to be apart for each of the liquid jetting heads. Different sorts of solutions (for example, the solution of organic semiconductor material and the solution of electrodes) can be made to jet from the respective liquid jetting heads separately. Alternatively, these may be mounted on separate carriages as separated head units respectively, so that the respective solutions are positively prevented from being mixed on nozzle surfaces.
The light emitting type organic thin-film transistor device producing manufacturing apparatus jets the organic semiconductor material solution and the electrode producing solution, and thus, produces the light emitting type organic thin-film transistor device. Since the plurality of sorts of solutions can be jetted as mentioned above, the light emitting type organic thin-film transistor device can be easily produced from a combination of the electrode pattern producing solution and the organic semiconductor material solution.
Other features of the apparatus for manufacturing/producing the light emitting type organic thin-film semiconductor device according to the present invention will now be described. A study for a better way for liquid drops to be positively adhere to the substrate after they being jetted, and to produce satisfactory patterns, will now be described.
As described above, in the manufacturing apparatus applicable for producing the light emitting type organic thin-film transistor device according to the present invention, the jetting head unit 11 moves with a fixed distance from the substrate 14 in the X/Y directions parallel from the light emitting type organic thin-film transistor group producing surface. Then, patterns or the light emitting type organic thin-film transistor group are produced. That is, the jetting head unit 11 moves parallel to the substrate 14 surface. Alternatively, the substrate 14 itself may instead move with respect to and parallel to the jetting head unit 11.
During this process, high accuracy patterns or light emitting type organic thin-film transistor device groups can be produced when liquid drop jetting is carried out in a condition in which the mutual movement is stopped each time when liquid drop jetting is carried out for producing the pattern or the light emitting type organic thin-film transistor device group. However, this manner may remarkably degrade the productivity. Therefore, the mutual movement is actually not stopped, and solution jetting is carried out continuously in sequence. In this case, the mutual movement speed (for example, the X direction moving speed of the carriage of
These factors were eagerly studied, upon studying for the manufacturing method applied for producing a light emitting type organic thin-film transistor device according to the present invention. As a result, the inventors had found out that the jetting speed should be higher than the mutual movement speed. When the jetting head unit 11 is kept to have a fixed distance from the substrate 11, moves in the X/Y directions mutually with respect to the substrate 14, jets the solution and produces the pattern or the light emitting type organic thin-film transistor device group, a liquid drop of the solution is made to adhere to the substrate 14 at a speed corresponding to a combined vector of the mutual movement speed and the jetting speed. As to the positional accuracy, a liquid drop can be made to adhere at a desired position as a result of a distance between the substrate 14 and the solution jetting nozzle surface of the jetting head unit 11, and the above-mentioned combined vector speed being appropriately taken into account, and timing of jetting begin appropriately selected.
However, even when adherence can be made at a desired position, if the mutual movement speed is too large, the adhering liquid then flows on the substrate 14 due to the mutual movement speed, and thus, the satisfactory shape pattern or light emitting type organic thin-film transistor device group may not be produced. Upon studying for the manufacturing apparatus applied for producing a light emitting type organic thin-film transistor device according to the present invention, this point was especially taken into account. An example of a result of the study will now be described. In this example, the apparatus of
In addition to such evaluation, a resistance value between top and bottom ITO transparent electrodes was measured, and thus, a line disconnection due to unsatisfactory dot position or a resistance shift due to connection with adjacent row, was evaluated. In a measurement result below, ◯ denotes a desired resistance value. X denotes a resistance value different from the desired one.
Details of the experiment conditions are as follows: A substrate used was a glass substrate with transparent ITO electrodes. The above-mentioned Ag fine particle included solution (specifically, a fine particle diameter: 0.005 μm) was combined with the jetting head (nozzle diameter: 5 μm) of
The jetting head used was of a piezo type, had 64 nozzles and their arranging density was 100 dpi. The jetting head and the substrate carried out mutual movement (i.e., the substrate was fixed, while the jetting head was carried by a carriage for scanning). The movement was controlled on the μm order. Also, jetting timing was controlled. Thus, as mentioned above, dot adherence with the pitch of 4 μm pattern were produced with the center-to-center distance kept of 12 μm.
In order to change the jetting speed, a driving voltage input to the piezo device for liquid jetting was changed between 15 through 22 V. A driving frequency was 12 kHz. In the jetting head employing the piezo device, the jetting speed can be changed as a result of the input voltage to the piezo device being changed. However, a mass of the jetted drop would change also simultaneously. Therefore, by controlling the driving waveform (a rising up waveform and a decaying down waveform including a drawing jetting manner) so that only the jetting speed was changed.
Further, a shape of a drop, when it was jet and flied in a condition the same as that of actual pattern production, was observed. Then, the driving waveform was controlled so that the shape became approximately spherical immediately before (2 mm in this example) adhering the substrate surface (see
TABLE 1
Experiment
carriage
resistance
jetting
X-direction
pattern
value
speed
moving speed
produced
No.
Vj(m/s)
Vc(m/s)
state
1
3
1
∘
∘
2
3
2
∘
∘
3
3
3
x
x
4
3
4
x
x
5
5
1
∘
∘
6
5
2
∘
∘
7
5
3
∘
∘
8
5
4
∘
∘
9
5
5
x
x
10
5
6
x
x
11
7
2
∘
∘
12
7
3
∘
∘
13
7
4
∘
∘
14
7
5
∘
∘
15
7
6
∘
∘
16
7
7
x
x
17
7
8
x
x
18
10
4
∘
∘
19
10
6
∘
∘
20
10
8
∘
∘
21
10
10
x
x
22
10
12
x
x
23
10
14
x
x
24
12
4
∘
∘
25
12
6
∘
∘
26
12
8
∘
∘
27
12
10
∘
∘
28
12
12
x
x
29
12
14
x
X
From the above result, it is seen that, when the carriage X-direction speed is more than the jetting speed, no satisfactory pattern can be produced, and also, inter-electrode resistance value becomes one different from the desired one. In other words, it is seen that, in the manufacturing apparatus applied for producing a light emitting type organic thin-film transistor device according to the present invention, when a light emitting type organic thin-film transistor device is produced by a manner of, with the use of the jetting head employing the piezo device, liquid drops of the organic semiconductor material included solution being provided to the substrate, and being dried, the speed of the liquid drops jetted from the jetting head should be higher than the mutual movement speed between the jetting head and the substrate.
Furthermore, drop flying conditions of this example were such that, as mentioned above, the driving condition (driving waveform) was determined such that, a plurality of minute drops should be prevented from accompanying subsequent to the flying body drop. As a result, these plurality of minute drops, otherwise generated, could be completely prevented from adhering to unexpected positions. Thus, very satisfactory patterns could be produced.
Further, even though a rod like flying drop long along the flying direction was obtained, the length of the flying drop could be controlled by the driving waveform control to be within three times of the diameter (l≧3d) (see
As another method of producing the light emitting type organic semiconductor layer, a vacuum deposition method, a molecular ray epitaxial growth method, an ion cluster beam method, a low energy ion beam method, an ion plating method, a CVD meted, a spattering method, a plasma polymerization method, an electrolytic polymerization method, a chemical polymerization method, and so forth, may be used, depending on material to actually use.
As a film thickness of these organic semiconductor layers, although no special limitation exists, characteristics of the light emitting transistor may greatly depend on the film thickness of the organic semiconductor layer. The film thickness depends on each particular organic semiconductor. However, generally speaking, not more than 1 μm, specifically, 10 through 300 nm is preferable.
As electrode material of the gate electrode, the source electrode and the drain electrode of the light emitting type organic transistor device according to the present invention, platinum, gold, silver, nickel, chrome, copper, iron, tin, antimonial lead, tantalum, indium, palladium, tellurium, rhenium, iridium, aluminum, ruthenium, germanium, molybdenum, tungsten, tin oxide stibium, indium tin oxide (ITO), fluorine doped zinc oxide, zinc, carbon, graphite, glassy carbon, silver paste and carbon paste, lithium, beryllium, sodium, magnesium, potassium, calcium, scandium, titanium, manganese, zirconium, gallium, niobium, sodium, sodium-potassium alloy, magnesium, lithium, aluminum, magnesium/gold mixture, magnesium/copper mixture, magnesium/silver mixture, magnesium/aluminum mixture, magnesium/indium mixture, aluminum/aluminum oxide mixture, lithium/aluminum mixture and so forth may be used. When light emitted is taken out from the side of the electrode, a transparent electrode should be provided of transparent material such as ITO.
Other than using such material alone, a combination of a plurality thereof may be used. Specifically, a two-layer configuration such as that of a combination of magnesium/gold mixture and gold, a combination of magnesium/copper mixture and gold, a combination of magnesium/silver mixture and gold, a combination of magnesium/aluminum and gold, a combination of magnesium/indium mixture and gold, a combination of aluminum/aluminum oxide and gold. a combination of a lithium/aluminum mixture and gold, a combination of magnesium and gold, a combination of aluminum and gold, a combination of chrome and gold or such may be used. A three-layer configuration such as that of a combination of magnesium/gold mixture, gold and aluminum, a combination of magnesium/copper mixture, gold and aluminum, a combination of magnesium/silver mixture, gold and aluminum, a combination of magnesium/aluminum mixture, gold and alumiju8im, a combination of magnesium/indium mixture, gold and aluminum, a combination of aluminum/aluminum oxide, gold and aluminum, a combination of lithium/aluminum mixture, gold and aluminum, a combination of magnesium, gold and aluminum, a combination of aluminum, gold and aluminum, a combination of chrome, gold and aluminum or such may be used.
Other than such electrically conductive metal material, silicon semiconductor material may be used instead. Especially, for a case where the gate electrode 6 has a function of supporting member as shown in
Alternatively, well-known polymer improved in its electrical conductive by means of doping or such, for example, electrically conductive polyaniline, electrically conducive polypyrrole, electrically conductive polythiophene (complex of polyethylene dioxy thiophene and polystyrene sulphonate or such) may be preferably used.
As material as the source electrode and the drain electrode, among materials mentioned above, those having low electric resistance on a contact surface with the semiconductor layer are preferable. For a case of p-type semiconductor, especially, platinum, gold, silver, ITO, electrically conductive polymer and carbon are preferable.
These electrode layers and patterns are produced by a method in combination of a film producing method such as a vacuum deposition method, a molecular epitaxial growth method, an ion cluster beam method, a low energy ion beam method, an ion plating method, a CVD method, a spattering method, a plasma polymerizing method, a chemical polymerization method, a spray coating method, a spin coating method, a blade coating method, a dip coating method, a coating method, a role coating method, a bar coating method, a die coating method, or such, and a photolithography/etching method, or a lift off method.
Alternatively, a non-contacting direct producing method may be used by using the liquid jetting principle described above for producing the light emitting type organic semiconductor material layer. Further, a printing method such as letterpress printing, intaglio printing, litho printing, screen printing may be used.
When the source electrode, the drain electrode and so forth are produced of these solution or paste material, flowable electrode material such as solution, paste, ink, dispersion liquid or such including the above-mentioned conductive metal may be used. Thereamong, flowable electrode material including electrically conductive polymer, or, metal fine particles including platinum, gold, silver, or copper is preferable. Further, as solvent or dispersion medium, solvent or dispersion medium including water in the ratio of more than 60% or more preferably more than 90% for the purpose of reducing damage to the organic semiconductor may be used.
As the flowable material including metal fine particles, material obtained from dispersion metal fine particles having particle diameter of 1 through 50 nm, more preferably, 1 through 10 nm in water or any other dispersion medium which is organic solvent, with the use of dispersion stabilizer if necessary, may be used.
As material of the metal fine particles, platinum, gold, silver, nickel, chrome, copper, iron, tin, stibium, lead, tantalum, indium, palladium, tellurium, rhenium, indium, aluminum, ruthenium, germanium, molybdenum, tungsten, zinc or such may be used.
As a method of producing the dispersion of the metal fine particles, a physical producing method such as a gas evaporation method, spattering method, metal moisture combining method or such, a chemical producing method such as a colloid method, a coprecipitation method or such in which metal ions are reduced in liquid phase and metal fine particles are produced, may be used. However, preferable dispersion is metal fine particle dispersion produced by means of the colloid method or the gas evaporation method.
As the gate insulation layer of the organic thin-film transistor according to the present invention, various insulation films may be used. However, especially, inorganic oxide film having high dielectric constant is preferable. As the inorganic oxide, silicon oxide, aluminum oxide, tantalum oxide, titan oxide, tin oxide, vanadium oxide, barium titanate strontium, zirconium acid barium titanate, zirconium acid titanate lead, lead titanate lanthanum, strontium titanate, barium titanate, barium fluoride magnesium, bismuth titanate, strontium titanate bismuth, strontium tantalite bismuth, bismuth tantalate niobate, trioxide yttrium, and so forth may be used. Thereamong, silicon oxide, aluminum oxide, tantalum oxide and titanium oxide are preferable. Also, inorganic nitride such as silicon nitride, aluminum nitride or such are preferable.
As a method of producing the above-mentioned film, a dry process such as a vacuum deposition method, a molecular ray epitaxial growth method, an ion cluster beam method, a low energy ion beam method, an ion plating method, a CVD method, a spattering method, an atmosphere plasma method, a coating method such as spray coating method, a spin coating method, a blade coating method, dip coating method, a casting method, a roll coating method, a bar coating method, a die coating method, a wet process such as a method of patterning such as printing or ink jet, may be used. Any thereof may be used depending on material to use actually. Alternatively, for a case where the silicon semiconductor substrate has a supporting function and a gate electrode function (
As the wet process, a method in which, liquid in which the inorganic oxide fine particles are dispersed in any organic solvent or water with the use of surfactant or dispersion coadjuvant if necessary, may be carted and dried, or, a so-called sol-gel method in which oxide precursor such as alcoxide solution is located and dried, may be used.
Thereamong, the atmosphere plasma method is most preferable. Further, it is preferable that the gate insulating layer is made of anodized film or made of anodized film and an insulating film. The anodized film may preferably be one which has undergone a sealing process. The anodized film may be produced as a result of metal which can be anodized being anodized by a well-known method.
As the anodizable metal, aluminum and tantalum may be used. A specific method of anodizing processing is not limited, and a well-known method may be used. As a result of carrying out anodization processing, an oxide film may be produced. As electrolyte used in the anodization processing, any one may be used as long as it can produce a porous oxide film. Generally speaking, sulfuric acid, phosphoric acid, oxalic acid, chromic acid, boric acid, sulfuric acid, benzene sulfuric acid or such, mixed acid in combination of some thereof, or salt thereof, may be used. Processing conditions of the anodization processing may depend on electrolyte to use. Generally speaking, a concentration of the electrolyte should be within a range of 1 through 80 weight %, temperature of the electrolyte should be within a range of 5 through 70° C., an electric current density should be within a range of 0.5 through 60 A/dm2, a voltage should be within a range of 1 through 100 V, an electrolytic time should be within a range of 10 seconds through 5 minutes. Preferable anodization processing is such that water solution of sulfuric acid, phosphoric acid or boric acid is used as electrolyte, and a direct current power source is used. However, an alternative current power source may also be used. Concentration of these acids should be preferably 5 through 45 weight %. It is preferable that temperature of the electrolyte is 20 through 50° C., the electric current density is 0.5 thorough 20 A/dm2, and electrolyzing processing is carried out for 20 through 250 seconds.
As the organic compound film, polyimide, polyamide, polyester, polyacrylate, photo-curing resin such as photo-radical polymer, photo-cation polymer or such, copolymer including acrylonitrile ingredient, polyvinyl phenol, polyvinyl alcohol, novolak resin, cyanoethylpluran or such may be used.
As a method of producing the organic compound film, the above-mentioned wet process is preferable.
The inorganic oxide film and the organic oxide film may be used in combination. A thickness of these insulating films is, generally speaking, 50 nm through 3 μm, preferably 100 nm through 1 μm.
When the organic semiconductor is produced on the gate insulating layer, surface treatment may be carried out on a surface of the gate insulating layer. Self-organized orientation film of silane coupling agent such as octadecyltrichlorosilane, trichloromethylsilazane, alkane phosphoric acid, alkane sulfuric acid, alkane carbonic acid, or such, may be preferably used.
For a case where the gate insulating layer is configured such that, as described above, light emitted is taken out through the gate insulting layer, the gate insulating layer may be made of, for example, translucent material such as silicon oxide, whereby the light can be effectively taken out.
One preferable example of the supporting body is resin. In a configuration example shown in
Also in this case, in order to achieve a configuration such that light emitted is taken externally through a substrate or a sheet as the supporting body, translucent material is selected therefor from among the above-mentioned materials, whereby light can be effectively taken out therethrough.
The device protection layer 7 made of translucent material may be provided on the light emitting type organic thin-film transistor device according to the present invention. As the device protection layer, the above-described inorganic oxide or inorganic nitride may be used, and, preferably, may be produced by the above-mentioned atmospheric plasma method. Especially, silicon oxide which is translucent material is preferable. Thereby, oxide, vapor or such in the air, can be cut off, and thus, the organic semiconductor material can be sealed therefrom. Thus, durability of the thin-film transistor device can be improved, and also, light emitted from the organic semiconductor material can be effectively taken out.
For a more specific device structure of the light emitting type organic thin-film transistor device, description will now be made with reference to
This example is an organic transistor configured such that, an organic semiconductor layer 2 made of organic semiconductor material, for example, described above, is laminated in such a manner that the entirety of the pair of the source electrode 3 (first electrode) and the drain electrode 4 (second electrode) are disposed to be apart with a predetermined distance on a gate insulating layer 5, and the gate electrode 6 (third electrode) are provided in an area in which the organic semiconductor layer 2 is provided, through a gate insulating layer 5 located below. Between the source electrode 3 and the drain electrode 4, such a voltage is applied that the organic semiconductor material emits light. Further, a voltage is applied to the gate electrode 6, so that turning on/off of the light emission or a light emission amount, is controlled. At this time, it was found out that, by increasing an electrode length of the source electrode 3 and the drain electrode 4 in an area in which both face one another, light was emitted more efficiently.
This matter will now be described with reference to
In the case of
More preferably, the electrode patterns are produced in such a manner that the ratio between both (l/w) may be 1/2000 through 1/2. In this case, simple rectangular patterns as those shown in
In this example, ends at which the patterns of the source electrode 3 and the drain electrode 4 face one another have a comb tooth shape. There, the comb teeth are configured such that they pass each other as shown. Thereby, the electrode length w along which the source electrode 3 and the drain electrode 4 face can be effectively increased. Although not shown, a peripheral length of the comb teeth along which they face corresponds to the electrode length w of an area in which the source electrode 3 and the drain electrode 4 face one another. l shown corresponds to the inter-electrode distance between the source electrode 3 and the drain electrode 4.
This device is produced by a process such as that shown in
In this example, the substrate acts as both the supporting body 1 and the gage electrode 6. Therefore, the Si semiconductor substrate is used. However, in order to produce a very large number of light emitting type organic thin-film transistor devices in a very large area as described later, the costs can be reduced by using a glass substrate, a ceramic substrate or such, for the supporting body 1. Further, as mentioned above, a plastic film sheet may also be used. Further in such a case, silicon oxide which is translucent materiel may be used as the gate electrode 5, and the glass substrate or the plastic film sheet may be transparent. Further, also translucent material such as ITO may be used as the gate electrode not shown. Thereby, light emitted can be effectively taken out from the side of the supporting body 1 (in this example, the member as the gate electrode 6) opposite to the arrow A of
In
The organic semiconductor layer 2 was obtained as a result of, polymer (described above) expressed by the following chemical formula for example,
##STR00006##
in which 1.8 w % of Rubrene was added, being dissolved in dimethyl carbonate, and, then, the thus-obtained solution being coated on the above-mentioned source electrode 3 and the drain electrode 4, by means of the above-mentioned light jetting principle, without contact, in such a manner of so-called ‘solid jetting’ which terms is one used in the ink-jet recording technique. A thickness of the thus-produced organic semiconductor layer 2 was approximately 120 nm measured after it was dried.
After drying the organic semiconductor layer 2, silicon oxide was, as the device protection layer 7, by means of spattering, produced on the entire surface so that the organic semiconductor layer 2 could be completely sealed, for a thickness of 0.5 μm. Thus the light emitting type organic thin-film transistor device was completed.
Next, other features of the present invention will be described. As described above, in the present invention, an electrode length w of an area of mutually facing source electrode 3 and drain electrode 4 is larger than an inter-electrode distance l therebetween. More preferably, a ratio (l/w) of the inter-electrode distance l between the source electrode 3 and the drain electrode 4 and the electrode length w of the area in which the source electrode 3 and the drain electrode 4 face one another is made 1/2000 through 1/2. Thereby, the light emission can be more efficiently carried out. In other words, in
As can be seen from the above description, according to the present invention, in order to achieve more efficient light emission, a pattern configuration of the source electrode 3 and the drain electrode 4 are determined so that a light emission area has an elongate shape.
Further, by producing a plurality of the light emission areas in each of which the pair of electrodes 3 and 4 face one another, in a matrix manner, and also, shaping each of the plurality of light emission areas so that adjacent three areas form an approximately square of light emission area, transistor operation and light emission operation can be carried out in a single device, and thus, another useful, and new configuration of organic light emission type transistor can be provided, as will be described later.
Next, with reference to
As described above, according to the present invention, light emitted may be taken out in a direction of the arrow B of
For example, if, as shown in
Accordingly, in the present invention, as a configuration of the light emitting type organic thin-film transistor device, for a case where light is taken out through the gate electrode 6, the gate insulating layer 5 inserted therebetween should be made of translucent material, the gate electrode 6 pattern should be made of translucent material, and also, the gate electrode pattern should have a shape and/or size such as to cover an area wider than the area 8 from which the organic semiconductor material emits light.
The configuration examples of the light emitting type organic thin-film transistor device according to the present invention, and the examples of preferably usable materials have been thus described above. Next, a more specific usage example of the present invention is described. The present invention may be used as a light emitting device with the use of characteristics of the organic thin-film transistor providing light emission phenomena.
In the related art, when an organic transistor device is used as a display device, a device driving function is provided, in combination with a separately produced display device such as a liquid, an electrophoretic device, or an organic EL device.
In contrast thereto, according to the present invention, the organic transistor devices themselves may also act as light emitting devices (corresponding to the output devices 93). Accordingly, the above-mentioned output devices 93 such as liquid crystals, electrophoretic devices, or organic EL devices should not be separately provided. According to the present invention, as a result of the plurality of organic transistor devices being arranged in a matrix manner, and turning on/off of the organic transistor devices being carried out, they themselves can function as the output devices 93. Furthermore, in addition to a simple turning on/off control, a gate voltage may be gradually or stepwise changed. Thereby, a light emission amount can be controlled. As a result, they may be made to function also as the output devices 93 providing superior tone expression. That is, a very simple configuration of a self light emitting type display device, not requiring provision of the separate output devices 93 shown in
At this time, R, G and B are included in one pixel. For this purpose, the light emission areas may be made to have elongate shape (rectangular shape), and the light emission areas of the organic transistor devices arranged in a matrix manner may be arranged in close proximity in a short dimension direction. As a result, each pixel (as a unit including the three colors RGB) can be prevented from having such a remarkably elongate shape as that of an aspect ratio amounting to 3, for example, but each pixel may have an approximately square shape from the three elongate color filters disposed side by side (see
This matter will now be described in more detail.
In this example, the light emission area 8 of one light emitting type organic thin-film transistor device has a shape of a rectangular in a size of 28 μm by 90 μm. Corresponding thereto, a size of the filter is 35 μm by 105 μm. One pixel emitting the three colors RGB has a shape of a squire of 120 μm by 120 μm. The display device thus has a function of carrying out color display of 200 ppi (picture element per inch, or pixel per inch). It is noted that one pixel should not strictly be a square, but should be an approximately squire (for example, an aspect ratio in a range between 0.8 and 1.2).
The color filters F may be produced as a result of material such as glass substrate, a plastic substrate or such being colored. However, by using a glass substrate as a base, as will be described later, it may be used also as a member for sealing in an airtight manner the light emission part with the use of its rigidity. On the other hand, when organic material such as plastic film is used, the light emitting type organic thin-film transistor device sheet itself may be produced of the same organic material film. As a result, a display device which has a reduced weight and may be bent, may be achieved. Actually, material should be selected in consideration of the respective advantages.
In the figure, merely the matrix of 5 pixel by 3 pixel (each pixel corresponding to the RGB light emission areas) is shown. However, when the light emitting type organic thin-film transistor devices are actually applied in a color display device, the number of pixels used are thousands of pixels by thousands of pixels through tens of thousands of pixel by tens of thousands of pixels. A display area has a size of hundreds of mm by hundreds of mm through thousands of mm by thousands of mm.
Other features of the present invention will now be described. As described above, the respective light emitting type organic thin-film transistor devices according to the present invention may be separately protected by material such as silicon oxide having transparency and sealing property. Thereby, sealing performance can be positively provided.
On the other hand, in consideration of costs. a method of coating the entire surface of all the organic transistors 88 shown in
As another sealing method, the organic transistor sheet 88 itself shown in
Such a display device is assembled by the order shown in
As material of the protection substrate 98, a translucent member is selected for the purpose of taking emitted light externally therethrough. Pyrex (registered trademark) made by Corning Co., Ltd., or such, may be preferably used therefor. Alternatively, in consideration of crash proof property, chemical strengthen glass FL3.2 made by Nippon Sheet Glass Co., Ltd., or such, may be preferably used.
As another preferable configuration, inactive gas such as nitrogen gas may be injected in the gap 100 between the organic transistor sheet 88 and the protection substrate 98, and then, a sealed state may be provided. Thereby, high light emission efficiency can be obtained.
The above-mentioned color filters may be then disposed on the protection substrate 98 or between the organic transistor sheet 88 and the projection substrate 98. Alternatively, the color filters themselves may be produced in a glass substrate and may also be used as the protection substrate 98.
When the gate voltage was changed with −90 V of the drain voltage in a condition of the above-described light emitting type organic thin-film transistor device (without the device protection layer 7) according to the present invention shown in
In a vacuum state of 1×10−3 Torrs, the maximum brightness of approximately 2000 cd/m2 was obtained with the drain voltage of −90 V and the gate voltage of −90 V. Further, in a vacuum state of 1×10−7 Torrs, the maximum brightness of approximately 2500 cd/m2 was obtained with the drain voltage of −90 V and the gate voltage of −90 V. Further, also in a nitrogen gas injected state instead of such a vacuum airtight state, the maximum brightness of approximately 2400 cd/m2 was obtained with the drain voltage of −90 V and the gate voltage of −90 V. Next, the device projection layer 7 (silicon oxide) was provided on the entire surface of the light emitting type organic thin-film transistor device with a thickness of 0.5 μm and the device was thus sealed. Then, evaluation was made in the ordinary air. As a result, the maximum brightness of approximately 2200 cd/m2 was obtained with the drain voltage of −90 V and the gate voltage of −90 V. Therefrom, it was seen that the device could function even in the air when sealing was properly made.
Further, the present invention is not limited to the above-described embodiments, and variations and modifications may be made without departing from the basic concept of the present invention claimed below.
The present application is based on Japanese Priority Applications Nos. 2005-063197, 2005-063198, 2005-063199, 2005-063200 and 2005-063201, each filed on Mar. 7, 2005, the entire contents of which are hereby incorporated herein by reference.
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